The present invention is directed to the process for the removal of organic contaminants, in particular polychlorinated biphenyls (PCBs), from soil, sediments and sludges. All organic compounds having physico-chemical characteristics similar to PCBs can be removed by this process.
Contamination of sediments and sludges of various harbors, rivers and lagoons throughout the United States with PCBs and other organics is recognized to be a serious environmental problem. Specific PCB contamination sites of particular severity have been identified at Waukegan, Ill. and Bedford Harbor, Me., the Hudson river in New York and numerous industrial lagoons. Dredging to decontaminate such harbors/rivers and lagoons is unacceptable until effective disposal/treatment methods for the contaminated sediments become available. The detoxification of such contaminated sediments and sludges at economically acceptable costs presents a serious technological challenge if goals of having no more than 1-5 ppm PCBs in the tgreated sediments are to be met.
A major problem in the decontamination of soil, sediment and sludges is the high water content often encountered in the environment. This is particularly true if the sediment or sludge has to be dredged from a river basis or a lagoon. Water contents of 80% are not uncommon.
Treatment of PCB contaminated sediments and sludges in an incinerator complying with CFR761.70 is quite energy intensive and costly, if 99.9999 percent destruction and removal efficiencies for the PCBs are to be achieved. Exact costs are difficult to predict because it is uncertain what prices commercial incineration facilities will charge to accept the responsibility of handling such sensitive materials. Current estimates range from $1700 to $2000/m.sup.3 if the cost of disposal of residue from incineration are included. Chemical waste landfill disposal costs incurred when the contaminated sediments or sludges are placed in an authorized chemical waste landfill, are less expensive, but present other difficult problems. There exists therefore a very real need for an alternative process technology which is both technically and economically feasible for the cleanup of these PCB contaminated sediments and sludges.